This week I start working on shot _01 and shot_04, instead of totally turning the sense into the night view, I'll firstly try to match the light, the sky, the background, and the person in the same color tone.
My Responsibility for Week 5
Moodboard Reference
Convert Files to EXR & Work with ACES Workflow
3D Tracking & Camera Export
Pull the Key of the Actor
Overall Color-correction
1. Moodboard Reference
Since I need to color correct the first and last footage and turn it into zombie time, here I find pictures as the reference of the mystery environment.
2. Converting Footage into EXR Files with Nuke
The first shot and last shots consist of a seamless loop. When we doing the shooting, we began with the last one and then the first, which is a very long video that can be split into two parts.
Working on the whole footage in nuke without clipping would be much easier for 3D tracking, so here I import the mp4 file into nuke and reexport it as EXR sequences, use timeoffset node to reduce the first 500 frames which are unnecessarily needed, in this way, all the exported EXR frame count will start from 1. and the whole footage ranges from frame 1 to frame 1422, 60 fps.
Then, I set the color space into ACES_1.1, and set up the read footage into Utility - Linear - Rec.709, which keeps the footage colors looking as same as the mp4 file does.
3. Camera Tracking
I track the whole shot from frame 1 to frame 1422 by using the roto node as an input mask. The final solve error is 1.65, not a perfect number but it is enough to position the camera and pane.
The plane represents the ground, and the cube represents the position of the obelisk. I export the camera and geometries with the WriteGeo node.
View from the generated 3D Camera.
4. Pulling key of the Actor
4.1 Problems
The high contrast of the whole shot with high exposure and dark shadows (left)
The actor has white strips on his shirt which is the most white part of the scene (left)
Once darken the scene, the actor will be too dark compared with the background (right).
4.2 Methods
Separate the actor from the background (pull a key), then color-correct them separately
Since there is no greenscreen behind, and it is hard to roto the actor out, I use the keyer node multiple times and the Channel Merge node to get the rough silhouette as the alpha mask.
Multiple times of Channel Merge to get the result of the rough alpha channel.
Result of the extraction after refinements.
5. Overall Color correction
I color-correct the sky, background, and person separately to basically match the color tone, but there are a lot of details need to pay more attention to.
The node tree.
The Next Step
Refine the roto stuff
Sky replacement
Paint out the background person
Environment build
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